(Table 1) Interstitial water chemistry at DSDP Leg 72 Holes

Interstitial waters collected at Sites 515 and 516 during DSDP Leg 72 have been analyzed for major and minor constituents. At both sites increases in dissolved calcium and decreases in dissolved magnesium with depth imply reactions in the sediment column involving these constituents. It is suggested that these concentration changes are related to reactions involving biogenic silica transformation